1. Field of Invention
The invention relates to a high density connector structure for transmitting high frequency signals. More particularly, the invention relates to a connector for transmitting high frequency electronic signals with a frequency level up to more than Megahertz/Gigahertz (MHz/GHz), and a plurality of contacts are arranged to be high density in a specific cross-sectional of the connector.
2. Description of Related Art
Since the amount of data transmitted between plural electronic devices are increased continuously, in order to provide more friendly using experience for users, the speed of transmitting signals between the electronic devices are increased accordingly. In order to enable the users to transmit a large amount of data in a shorter time, except increasing the number of signal paths for transmitting electronic signals between the electronic devices, currently the general solution is increasing the frequency of the electronic signals transmitted between the electronic devices. The connector is a bridge for transmitting electronic signals between different electronic devices. Under the condition that the frequency of the electronic signals transmitted between the different electronic devices are increased continuously, also considering the unfavorable effect of the high frequency electronic signals passing through the connector, the cause of the unfavorable effect of the high frequency electronic signals should be controlled and take appropriate treatments to reduce the substantive effect, to make the high frequency electronic signals be integrally transmitted between the electronic devices.
Due to a trend of minimizing volumes of electronic devices, the entire volume of the connector should be reduced (i.e., the density of contacts in a specific cross-sectional is increased) accordingly, and in order to increase the number of paths for transmitting electronic signals in the connector, the distance between conductive contacts arranged on the connector is reduced continuously. However, the condition that the distance between conductive contacts arranged on the connector is reduced continuously and is unfavorable for the transmission of high frequency electronic signals. This is because that the high frequency electronic signals transmitted between the conductive contacts will easily cause the crosstalk, which further causes generation of noise to the original transmitted high frequency electronic signals.
In a known prior art, the U.S. Pat. No. 8,167,631 disclosed a card edge connector, which is a high density connector for transmitting high frequency electronic signals. The card edge connector is used for transmitting a differential signal, wherein two ground line contacts (G) are arranged respectively at the outer sides of two adjacent signal line contacts (S), so that the contacts are arranged in a G-S-S-G state. The card edge connector is mainly formed by fixing a plurality of signal line contacts B and ground line contacts C to an insulator A. As shown in FIG. 24, the card edge connector uses a common contact D to transversely over the two signal line contacts B and to connect the two ground line contacts C, so that the two ground line contacts C can exchange electrical charges with each other and thus have the same electric potential. In the description of the conventional art, in order to avoid that the signal line contacts B accidentally contact the common contact D, the signal line contacts B crossed by the common contact D are all provided with a groove (not shown). For this prior art, the difficult of forming the groove on a metal sheet for the signal line contacts B, the impedance variation of signal line contacts during the transmission of the high frequency electronic signals caused by the groove, the disadvantage that the signal line contacts B, the common contact D and the ground line contacts C should be assembled in different batches, and the like all show that the design of the card edge connector is not economical.
As shown in FIGS. 25, 25-1 and 25-2, in another known prior art the U.S. Pat. No. 7,524,193, which discloses a connector with excellent high frequency character, mainly formed by a built-in circuit board E, an insulator A, a plurality of signal line contacts B, a plurality of ground line contacts C and a metal shield F. The built-in circuit board E is positioned on the insulator A, and the plurality of signal line contacts B and the plurality of ground line contacts C are respectively welded on appropriate positions on the built-in circuit board E, so that the built-in circuit board E can be electrically connected with the circuit board outside the connector through the plurality of signal line contacts B and the plurality of ground line contacts C. In this prior art, the built-in circuit board E extends from the outer side of the insulator A towards the mating connector for a certain distance to form a tongue-shaped plate E1; the two opposite surfaces of the tongue-shaped plate E1 are each provided with a plurality of circuit contacts E11, and the connector can be mated and electrically connected with a mating connector through the circuit contacts E11 of the inner circuit board E.
In the disclosure of the U.S. Pat. No. 7,524,193, the circuit contacts E11 of the built-in circuit board E at least can be connected to appropriate signal line contacts B or ground line contacts C through the electronic circuit (not shown) on the built-in circuit board E. Therefore appropriate impedance compensation can be obtained by adjusting the circuit arrangement on the built-in circuit board E and by adjusting the welding positions of the built-in circuit board E, the signal line contacts B and the ground line contacts C, so as to reasonably control the electrical characters of the components of the connector. However, in the disclosure of this prior art, the connector is directly mated with the mating connector (not shown) through the circuit contact E11 on the tongue-shaped plate E1 so that when two connectors are subjected to a repeat mating and unmating test, the contacts of the mating connector will continuously swipe the circuit contact E11 arranged on two opposite surfaces of the tongue-shaped plate E1, which causes that the fibers at the edges of the tongue-shaped plate E11 may be scrolled during the mating and unmating test, and thus the structure of the tongue-shaped plate E1 is continuously damaged, finally causing the failure of the connector.
Since the connector structure for transmitting high frequency signals disclosed in the above two prior arts both have the disadvantage of inefficient, it is necessary to provide an improved design for the high density connector for transmitting high frequency electronic signals.